The present invention generally relates to portable telephones, and more particularly to speakerphone accessories for such devices.
Radio frequency communication systems, such as portable telephone systems, permit a user to communicate from locations within a broad geographic coverage area. Portable telephones generally have a compact size so that the user may more easily carry the telephone, and typically include a housing containing a transceiver circuit, a microphone, a low-level speaker, and a user interface. The user interface includes a keypad and a display. The low-level speaker is designed to produce sounds which are audible in a private mode, when the user positions the portable telephone with the low-level speaker near the user""s ear. A rechargeable battery attached to the housing typically powers the portable telephone. The battery has a limited life, and therefore the portable telephone is designed to operate at low power to increase the time period between battery recharging.
A hands-free accessory is an attachable external apparatus that allows the portable telephone to function in a manner similar to a conventional speakerphone. The hands-free accessory typically includes a larger speaker to produce sounds that are audible during speakerphone mode, in which the user""s ear is positioned a greater distance from the portable telephone than during private mode. As a result, the user has free use of his or her hands for other activities, such as taking notes, during a call. A conventional accessory typically includes a speaker requiring a separate source of power, and therefore the accessory is bulky and requires additional batteries or connection to an additional or alternate source of power.
A portable speakerphone is known which incorporates a speaker and other hands-free components for use as a speakerphone. The hands-free components are integrated into the speakerphone, and therefore are not provided as an auxiliary feature that may be added to an existing portable telephone. As a result, the portable speakerphone is less compact. Also, if a user already has a portable telephone, a portable speakerphone is overly costly in that it requires the purchase of an additional telephone, rather than simply an accessory attachable to the existing portable telephone.
Therefore, there is a need for a speakerphone accessory capable of being attached to a portable telephone and running off the power supply provided to the portable telephone.